Air conditioning apparatus



May 10, 1960 J. w. KREUTTNER AIR CONDITIONING APPARATUS Filed May 4,1955 S9THERMOSTAT I/PRESSURE RELAY INVENTOR Jose 0k Wlirevll'mr A 9. hHam 7: ATTORNEYS AIR CONDITIONING APPARATUS Joseph W. Kreuttner, NorthTarrytown, N.Y., assignor to Buensod-Stacey, Incorporated, New York,NFL, in corporation of Delaware Application May 4, 1955, Serial No.506,022

2 Claims. (Cl. 236-13)" This invention relates to new and improved flowcontrol devices for air conditioning systems wherein warm and cold airare supplied separately to a mixing and distributing unit in a zone orroom being conditioned.-

The present invention is particularly adapted for high pressure airconditioning systems of this type, but it may be used to advantage forother systems. High pressure systems are those in which the pressure isover about 2 of water static pressure and the potential velocity of theair in the air ducts is between about 1500 to 3500 feet per minute.

In air conditioning systems of this type, flow conditions changecontinuously, especially as a result of variation in air demands in thezones, and it has been found that by controlling the flow rate into theindividual zones so as to maintain the flow substantially constant, theundesirable noise associated with the operation of air distributingunits of such systems is substantially eliminated.

It is an object of this invention to provide new combinations of airmixing and air volume controls for air distributing units for airconditioning systems of the above mentioned type, by which substantiallyconstant flow rates of conditioned air into the individual zones aremaintained during the operation of the system.

Another object of this invention is to provide a unitary proportioningdamper and air volume control device, which is simple and compact inconstruction and operation, reliable in performance, and readilyadjustable so that air temperature and volumetric rate of air de liverycan be set and automatically maintained at any preselected value withina wide range.

According to one feature of this invention, the air mixing anddistributing unit for individual zones is formed with adjoining cold airand warm air plenum chambers that are respectively connected with warmand cold air supply ducts. Each of the warm and cold air chambers has afluid connection with a mixing chamber in the unit through flowresistance plate means having apertures which are traversed by the airpassing from the warm and cold air chambers into a mixing chamber. Themixed air is subsequently discharged into the room or zone beingconditioned. Flow through the apertures in the flow resistance platemeans is controlled by a pair of dampers, one of which is disposed onthe upstream side of the plate means and the other of which is disposedon the downstream side of the plate means. The damper on the upstreamside of the plate means is movable to vary proportionally the aperturestherein open to the respective warm and cold air chambers forproportioning the Warm and cold air admitted into the mixing chamber soas to maintain the air discharged into the room at preselectedtemperatures. Merely by way of example, a thermostat such as shown inSerial No.

365,379 filed July 1, 1953, now Patent 2,794,598 granted June 4, 1957,may be used; The damper on the downstream side of the plate means ismovable w'vary the size of the efiective open area of the aperturestherein to control the total volume rate of flow from both warm and coldair chambers into the mixing chamber. The latter damper is preferablyoperated by a fluid pressure operated motor which utilizes air underpressure from the supply ducts to operate the same, the effective airpressure acting on the motor being controlled by a pilot memberresponsive to static pressure in the mixing chamber. I 7

Another feature of this invention is the provision of a damper in theform of an apertured. plate slidably mounted on the upstream side of theapertured walls, through which air is passed from air supply chambersinto the air mixing chamber, for movement relative thereto to bring itsapertures in and out of registry with the apertures in such walls.Theside of the apertured plate bearing against the apertured walls has afelt covering that bears against the apertured walls under the force ofthe pressure in the supply chambers on the plate and serves to seal theopenings in the wall against leakage in. addition to its normal functionof reducing fric' tion when the plate is moved relative to such walls.

These and other objects, features and advantages of the invention willbecome apparentfrom the following detailed description of theaccompanying drawings which are merely exemplary.

In the drawings:

Fig. 1 is a vertical section through an air distributing unit embodyingthis invention;

. Fig. 2 is a fragmentary perspective view of a portion of the damperassembly; and

Fig. 3 is a fragmentary vertical section showing another embodiment ofthis invention.

Referring now to Fig. 1 of the drawings, an air mixing and distributingunit or box in accordance with this invention is shown which comprises acasing 10 having therein in juxtaposition a cold air supply plenumchamber 12 and a warm air supply plenum chamber 14, which arerespectively connected with a cold air supply duct 16 and a warm airsupply duct 18. The top walls 20, 20' of chambers 12 and 14 are coplanarand are provided with a plurality of apertures 22 and 22' that formopenings for the upward passage of air from the respective plenumchambers into an air mixing chamber 24 within the casing 10. In thepreferred embodiment shown, the openings 22 and 22' take the form of aseries of elongated slots extending transversely in the casing 10 andarranged in tandem on both sides of the partition 26 which separates thewarm and cold air chambers. The mixed air is discharged into the zone orroom from the distributing box through opening 28 in the top wall ofcasing 10.

In accordance with the present invention, an improved volume and mixingcontrol arrangement is provided which includes a thermostaticallycontrolled warm air and cold air proportioning damper 30 arranged on theupstream side of discharge openings 22 and 22 and a throttle damper 40on the downstream side of discharge openings 22 and 22 which iscontrolled automatically to maintain a preselected volumetric rate offlow into the room during the operation of the air conditioning system.

The proportioning damper 30 is in the form of a flat plate and isslidably mounted for lateral movement on the underside of the top Walls20, 20'. The damper 30 has a series of apertures 31 which correspond insize and shape to discharge apertures 22 and 22'. The spacing betweenthe apertures 31 corresponds generally to the spacing between dischargeopenings 22 and 22, but the apertures 31 are so arranged that when theapertures on one side of partition 26 are in registry with openings 22',the apertures on the other side of the partition are otfset laterallyand out of registry with the discharge openings Patented May 10, I96022. Therefore, when the openings 22 are fully open, the openings 22' arefully closed.

It will be seen from Figure 2 that the slotted form of the openings indamper 30 and top walls 20, minimize the amount of the displacementrequired of the damper for bringing the apertures 31 completely in andout of registry with apertures 22 and 22'.

Movement of the proportioning damper is con trolled by athermostatically operated bellows motor 36. which has a plunger 36aconnected with the damper 30 by an angle piece 37, one arm of which isaffixed to the damper and the other arm aflixed to the plunger. Althoughthe damper operating motor is shown as an air motor, it is to beunderstood that other types of motors, such as an electric motor, areequally suitable. In the form shown, the motor 36 has a pressure relay38 connected with a thermostat 39 disposed in the zone or room beingcontrolled. A compression spring 36b continuously urges the bellowsmotor 36 to its deflated position in which the damper 30 is held in aposition providing maximum warm air flow and minimum cold air flow intothe mixing chamber 24. It will be understood that when the temperaturein the zone increases, the thermostat will produce an increase in thepressure of the air within bellows motor 36 expanding the bellows andmoving the damper 30 to the right as viewed in Figure 1 so as to reducethe effective size of the apertures open to the warm air chamber 14 andincrease the effective size of the apertures open to the cold airchamber 12, thereby reducing the proportionate amount of warm air andincreasing the proportionate amount of cold air admitted into the zone.When the temperature in the zone decreases, the reverse operationoccurs.

A felt mat 32 having apertures 34 corresponding to and aligned withapertures 31 is provided on the damper 30 between the damper and the topwalls 20, 20' of the warm and cold air supply ducts. This plate not onlyserves to reduce friction when the damper 30 moves back and forth on theunderside of top walls 20, 20' but also serves as a seal to preventleakage through the openings 31, 22 and 22 under the action of thepressure in the plenum chambers 12 and 14 against plate 30 which causesthe felt mat 32 to bear firmly against the underside of walls 20, 20'.

The volume control damper 40 is slidably mounted for lateral movement onthe upper surface of walls 20, 20' and has a plurality of apertures 41,corresponding in size, shape and arrangement with discharge openings 22and 22', that are movable into and out of registry with such dischargeopenings to increase and decrease the effective total open area of theopening 22 and 22 in a manner to maintain a predetermined constantvolume of air flowing in the mixing chamber and into the zone.

The damper 40 is operated by a fluid pressure motor 43 that is connectedwith the damper 40 by a plunger 44 and an angle bracket 45. The fluidpressure motor 43 utilizes air from the supply ducts to operate thesame, the motor being connected to both the warm air supply chamber 14and the cold air supply chamber 12 by a fluid line 46 having branches 47and 48 leading to the respective chambers. Alternatively, the fluidsupply line to the fluid pressure motor 43 may be connected to only oneof the air supply chambers.

The operating pressure in the motor 43 is controlled by a regulatingdevice, indicated generally at 50, in the mixing chamber 24. Theregulating device 50 includes an orifice 51 in fluid line 46 that servesto vent the pressure in said line into the mixing chamber. Flow throughthe orifice 51 is controlled by a valve plate 52 movable to and from aseated position closing such orifice by a pressure operated diaphragm53, which is connected to the valve plate 52 by a member 54. Diaphragm53 is subjected on one side to static pressure in air mixing chamber 24and to atmospheric pressure on its other side, the diaphragm, chamber 55being opened to the atmosphere through vent 56. A spring 57 is providedin chamber 55 to continuously urge the diaphragm to a position unseatingvalve plate 52.

When the volumetric rate of flow into the room increases as a result ofthe change of variable conditions in the supply ducts, the staticpressure within mixing chamber 24 increases and is operative upondiaphragm 53 of the regulating device 50 to move the valve plate 52toward a seated position closing the orifice 51. When this happens, thepressure within the motor 43 increases and effects a movement of thedamper 40 to the left, as viewed in Figure 1, so as to reduce theeffective size of the V discharge openings 22 and 22' and thereby reducethe total volume admitted from both the warm and cold air supply ducts,regardless of the proportioning damper setting. Upon a decrease in thevolumetric rate of flow into the zone, the spring 57 will act to returnthe diaphragm toward its normal unstressed position so as to open theorifice 51 and elfect a reduction in pressure in motor 43. When thisoccurs, a compression spring 49 bearing bearing against the free end ofthe motor 43 moves it in a direction in which it moves the damper 40 tothe right, as viewed in Figure 1, so as to increase the effective sizeof discharge openings 22 and 22 and thereby increase the total volume ofair flowing through such discharge openings.

The control thus provided is extremely sensitive and accurate over awide range, for it employes a diaphragm sensitive to relatively smallvariations in static pressure in the mixing chamber to act as a pilotmember for changing the pressure of the air within motor 43 so as tocause a force proportional to the force produced by the increase ordecrease in such static pressure but much larger than such force to acton the damper motor 43.

It will be seen that the felt mat 42 on the underside of damper 40serves to reduce friction when the damper 40 is moved back and forth onthe top walls 20, 20'. The air flowing through the discharge openings 22and 22' will tend to raise the damper 40 away from the top walls 20, 2t)and in this way complete closure of the discharge openings is avoided.

Another embodiment of the invention is shown in Figure 3 wherein allparts corresponding to the embodiment of Figure 1 are indicated by likereference numerals. In this embodiment volume control is separated fromair mixing. As seen in Figure 3 of the drawings, a resistance plate orgrid 60 is disposed in spaced relation to walls 20, 20' on thedownstream side of the discharge openings 22 in such walls. 60 is formedwith end flanges 61 by which it is supported on the top walls 20, 20',the flanges 61 also serving to form with the resistance plate '60 andwalls 20, 20 a chamber 64. The resistance plate is formed with a seriesof apertures 62 corresponding to the discharge apertures 22 and 22 andthrough which the air passed through apertures 22 must pass to enterchamber 24 in the box 10.

On the downstream side of the openings 62 in resistance plate 60, thevolume control damper 40 is mounted for sliding movement to bring theapertures 41 in and out of registry with discharge apertures 62 andfunctions in the same manner as that of the volume control damperembodiment described in Figure 1.

It will be understood that the foregoing detailed description and theaccompanying drawings are illustrative and that the improvements hereindisclosed may be embodied in the various forms of construction withinthe scope of the appended claims.

it will be understood that the foregoing detailed description and theaccompanying drawings are illustrative and that the improvements hereindisclosed may be embodied in various forms of construction within thescope of the appended claims. 7 I Y The resistance plate What is claimedis:

1. In an air conditioning distributing unit, air volume and temperaturecontrol means for an air conditioning system and the like, thecombination comprising an air mixing chamber, warm and cold air plenumchambers, flow resistance plate means having apertures therein to betraversed by air passing from each of said plenum chambers into saidmixing chamber, movable plate means positioned adjacent opposite sidesof said resistance plate means and having apertures therein to registerwith the apertures in said resistance plate means for admitting airtherethrough from the respective plenum chambers into said mixingchamber, one of said movable plate means having its apertures arrangedto proportion the relative amounts of warm and cold air admitted throughsaid resistance plate means and the other of said movable plate meanshaving its apertures arranged to vary the total volume of airflowingthrough said resistance plate means, power-operated means indriving relation to each of said movable plate means, ambienttemperature responsive thermostat control means connected with thepower-operated means associated with said one movable plate means formaintaining desired room temperature, and control means connected withthe poweroperated means associated with said other movable plate meansand responsive to pressure changes in said mixing chamber formaintaining a constant volumetric rate of flow through said resistanceplate means.

2. In an air conditioning distributing unit, air volume and temperaturecontrol means for an air conditioning system and the like, thecombination comprising an air mixing chamber, warm and cold air plenumchambers, flow resistance plate means having apertures therein to betraversed by air passing from each of said plenum chambers into saidmixing chamber, movable plate means positioned adjacent opposite sidesof said resistance plate means and having apertures therein to registerwith the apertures in said resistance plate means for admitting airamounts of warm and cold air admitted through said re sistance platemeans and the other of said movable plate means having its aperturesarranged to vary the total volume of air flowing through said resistanceplate means, fluid pressure operated means in driving relation to saidother movable plate means, said fluid pressure operated means having afluid connection'with at least one of said air plenum chambers forpassing air under pressure to such fluid pressure operated means, andmeans responsive to pressure changes in said mixing chamber to vary thepressure acting on said fluid pressure operated means proportionally tosaid changes so as to maintain a constant volumetric rate of flowthrough said resistance plate means.

References Cited in the file of this patent UNITED STATES PATENTS699,352 Titus May 6, 1902 1,780,589 Hendrix Nov. 4, 1930 2,425,000 PagetAug. 5, 1947 2,601,231 Smith June 24, 1952 2,625,331 Jordan Jan. 13,1953 2,641,871 Ray June 16,1953 2,705,595 Carlson et al. Apr. 5, 19552,772,695 Harrison Dec. 4, 1956

